An air-fuel mixture for an internal combustion engine is harder to ignite when cold, leading to less complete combustion and increased emissions. Once the engine has warmed up, the cylinders may warm the air-fuel mixture sufficiently. However, at startup, the engine may have no heat to contribute to the air-fuel mixture. Cold start conditions are especially severe when the ambient air temperature is low. An intake air heating system may be used to heat air arriving at the engine. This system may be located within or prior to the intake manifold. The intake air heating system may be brought up to temperature prior to attempting to start the engine.
Heating the intake air may allow for easier ignition and may hold the fuel in suspension more effectively, leading to fewer fuel droplets falling out of suspension in the air. Intake air heating systems may allow for faster starts of the engine, may reduce startup emissions (sometimes evidenced as “white smoke”), reduce engine wear, reduce overall battery consumption during startup, and reduce startup fuel consumption.
In FIG. 1, a not-to-scale illustration of a truck 100 includes an engine 104 and an air heater 108. While not shown, the intake manifold for the engine 104 may contain the air heater 108. Based on a control signal from an engine controller 112, an air heater controller 116 connects a battery 120 to the air heater 108.
For example, the air heater controller 116 may include an electromechanical relay. The air heater controller 116 may also include a timer so that the air heater 108 does not reach an over-temperature condition. However, if the engine 104 is started from a warm condition, where the air heater 108 is not cold but warm, this time-out may be too long, and the air heater 108 may experience an over-temperature condition. This may increase wear on the air heater 108.
The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.